PROJECT SUMMARY Retinal degeneration leads to progressive vision loss in millions of Americans. Promising cell replacement therapies have transplanted stem and progenitor-like cells (STLC) to replace damaged photoreceptors, but have yet to achieve the synaptic integration needed to restore Human vision. This deficit is largely because donor cells must maneuver a complex retinal environment, whose physio-chemical cues of damage impact donors in ways that remain underexplored. This project will create a predictive microfluidic-eye explant model to evaluate the extent to which external electro-chemotactic (EC) stimuli can guide the integration of photoreceptor replacements via a DNA topoisomerase II beta (Top2b) pathway. The research group has collectively demonstrated that STLC migrate large distances in response to external EC stimuli and used bioinformatics to target Top2b-regulated pathways as, both, significant to EC-induced migration and critical to synapse formation in the photoreceptor layer. Studies will first determine the range of clinically-applicable EC fields able to produce the directional migration of cone progenitors and correlate several metrics of cone cell movement with its Top2b expression. Experiments will then identify mechanistic roles of Top2b in retinal repair via quantitative pairing of EC-induced cell integration with genetic cell manipulation. Upon completion, the project will have developed a tunable, experimental model to manipulate the migration and synapse formation of STLC groups within retinal tissue using external fields. This translational system will facilitate the screening of new therapeutic targets, strategies and compounds to advance transplantation outcomes.